Some conventional image-forming devices, such as laser printers, are provided with a photosensitive drum, a developing device, and a toner box mounted on the case of the developing device for accommodating toner.
The toner box has an arc-shaped peripheral surface, for example, with a toner outlet formed in the arc-shaped peripheral surface for discharging toner into the developing device. A sealing member is provided around the toner outlet to prevent toner from leaking from the toner box. A shutter is slidably disposed on the outside of the arc-shaped peripheral surface for opening and closing the toner outlet.
After the toner box is mounted on the case of the developing device, the toner outlet is opened by sliding the shutter to a position not opposing the toner outlet. Through this operation, toner in the toner box can be supplied to the developing device through the toner outlet.
In an image-forming operation, the conventional image-forming device having the structure described above forms an electrostatic latent image on the surface of the photosensitive drum. A developing unit of the developing device develops the latent image into a toner image. When the toner box begins to run out of toner as the toner is consumed in image-forming operations, an operator removes this toner box from the case of the developing device and mounts a new toner box in its place.
Before the operator removes the toner box from the case of the developing device, the operator slides the shutter to a position opposing the toner outlet so that the shutter closes the toner outlet. In this state, the shutter is in close contact with the sealing member, which seals the gap between the shutter and the periphery of the toner outlet. Thus, this construction prevents toner in the toner box from leaking out through the toner outlet after the toner box has been removed from the case of the developing device.
However, toner will possibly leak through the toner outlet from the toner box if the shutter is moved from the closed position to the open position after the toner box is removed from the case of the developing device and is taken out of the main body frame of the image forming device. Further, the shutter will possibly be bumped against an ambient component due to the operator's inadvertent handling of the boner box, thereby breaking down the shutter.